Murison began looking at centroiding issues regarding the proposed Trex geodetic astrolabe. Murison took a sequence of short-exposure images of the double star Mizar during the daytime (and hence suitably unstable seeing) with a similar-size refractor as that used in the Trex instrument, in order to discern likely behavior of the latter and to have similar data for analysis. He is modeling centroiding methods using Maple.
While reviewing the Trex geodetic astrolabe design review, Murison became concerned at the apparent lack of a calibration method. The instrument puts a spot on the CCD that corresponds to the local zenith, but that needs to be calibrated directly to the onboard inclinometer zero point. Murison and Kaplan came up with a way to directly tie the zenith spot to the inclinometer by means of a simple external calibration setup using a mercury mirror, beamsplitter, and retroreflector. It appears that the retroreflector beam deviation tolerance is quite tight. Murison is currently analyzing the behavior of the calibration optics analytically with his ray tracing package AESOP (An Extensible Symbolic Optics Package), which uses the Maple computer algebra system.
Murison continued work on his new restricted three-body code for satellite capture. Currently there is a problem somewhere in the conversion of orbital elements from rotating-pulsating coordinates to the inertial frame.
